VMJ cells requires uniform intensity for proper operation. Cells are 9mm x 9mm square and 0.05cm thick. It consist of 40 junctions producing about 23 volts.
The intensity of the light on each junction becomes fairly uniform when the energy at the front and the back focus are combined at very high concentration level . 50% of the light fall on the front of the cell. The rest is reflected to the back of the cell with a mirror.
The cell will be cooled by immersing it in circulating deionised water in a sealed container. Because of the high voltage, electrolysis of the water will be observed.
The 395mm square fresnel lens is available as part number BHPA330-2-4 from http://www.bhlens.com/fresnel_lens.aspx
run 'fresnelx w395 g395 l330 e99.99 s40 r21 c20:4.5 c38:4.5' first to calculate the concentration levels
fresnelx w395 g395 l330 s40 r21 11493.911 2456.038 v.225
887.65W/m2 refractive index at 589.2nm(1.492) m(20), eff(99.990%) SunHalfAngle(0.26657o)
Total input energy 138 Watts
Acrylic Fresnel Lens Width 395mm x 0.405mm, Area 0.16m2, Focal Length 330mm (f/0.835), 395 grooves
Slice Radius Power Tot Tot QEff Ix Ax Area UV Blue Green Red NIR IR
390 492 622 760 1110 4000
mm W W % % mm2 % % % % % %
0 138.50 138 100.0 50.8 1.0 1.0 156025 5.6 13.0 19.6 18.2 27.5 16.0
Cell 1 Concentration Level 1493.911x, distance from lens 321.462mm, 0.9741f, nominal radius 5.766mm
1 0.225 9.43 9 6.8 68.1 66793.5 66793.5 0.16 6.9 3.3 0.0 0.3 73.7 15.7
2 0.450 8.43 18 12.9 48.3 19914.2 31634.6 0.48 8.0 3.9 0.0 1.0 52.9 34.2
3 0.675 8.62 26 19.1 44.2 12207.8 20841.5 0.80 8.2 4.2 0.0 1.9 48.8 36.9
4 0.900 6.38 33 23.7 52.8 6456.5 14548.3 1.11 12.0 6.5 0.0 7.7 53.5 20.3
5 1.125 5.66 39 27.8 52.8 4457.3 10915.7 1.43 15.1 9.5 0.0 15.6 44.8 15.0
6 1.350 5.54 44 31.8 50.4 3569.3 8671.0 1.75 17.0 15.7 0.0 24.8 29.9 12.6
7 1.575 7.70 52 37.4 48.1 4196.3 7483.9 2.07 8.3 33.0 6.0 31.7 10.9 10.0
8 1.800 9.32 61 44.1 50.7 4401.6 6761.5 2.39 1.8 25.9 14.8 31.0 15.3 11.2
9 2.025 8.36 69 50.1 51.0 3482.4 6073.3 2.70 1.9 21.4 16.4 32.2 16.2 12.0
10 2.250 7.72 77 55.7 50.9 2877.3 5466.1 3.02 1.9 19.8 18.4 31.0 16.5 12.3
11 2.475 7.22 84 60.9 50.8 2436.1 4940.2 3.34 1.9 18.2 20.4 29.9 17.0 12.6
12 2.700 6.74 91 65.8 50.6 2074.7 4482.5 3.66 1.9 16.9 22.7 28.0 17.4 13.0
13 2.925 6.27 97 70.3 50.5 1776.0 4082.1 3.98 2.0 15.1 25.2 26.5 17.7 13.5
14 3.150 5.86 103 74.6 50.2 1536.3 3731.5 4.29 2.0 13.7 28.0 24.4 17.9 14.0
15 3.375 5.47 109 78.5 49.8 1336.0 3422.7 4.61 2.0 12.3 31.9 21.2 18.0 14.5
16 3.600 5.14 114 82.2 49.5 1175.1 3150.5 4.93 2.1 10.9 39.3 14.8 18.0 15.0
17 3.825 4.84 119 85.7 49.7 1038.0 2909.3 5.25 2.1 9.2 40.2 14.7 18.6 15.3
18 4.050 4.56 123 89.0 49.9 923.6 2694.8 5.57 2.0 8.0 40.4 15.2 19.3 15.2
19 4.275 4.28 128 92.1 50.4 819.3 2502.6 5.88 2.0 6.6 40.6 15.8 20.2 14.8
20 4.500 4.03 132 95.0 51.0 731.5 2329.9 6.20 2.1 5.1 41.0 16.4 21.0 14.4
Cell 2 Concentration Level 456.038x, distance from lens 345.453mm, 1.0468f, nominal radius 10.436mm
run 'fresnelx w395 g395 l330 s40 r21 11493.911 29109.688' to calculate the radius and placement of the mirror. 9109.688 = (330 / (330 - (345.453 + 321.462) / 2)) ^ 2
Visualisation of tracking error from 0 to 1 degree in step of 0.02 degree. The image at the top right corner is the reflection of the back of the absorber. The average concentration level over both surfaces is 914 = 395 * 395 * 0.95 / (2 * 9 * 9)
The 420mm square fresnel lens is available as part number BHPA330-2-2 from http://www.bhlens.com/fresnel_lens.aspx
run 'fresnelx w420 g700 l330 e99.99 s40 r21 c20:4.5 c37:4.5' first to calculate the concentration levels
fresnelx w420 g700 l330 s40 r21 11882.951 2367.923 v.225
887.65W/m2 refractive index at 589.2nm(1.492) m(20), eff(99.990%) SunHalfAngle(0.26657o)
Total input energy 157 Watts
Acrylic Fresnel Lens Width 420mm x 0.248mm, Area 0.18m2, Focal Length 330mm (f/0.786), 700 grooves
Slice Radius Power Tot Tot QEff Ix Ax Area UV Blue Green Red NIR IR
390 492 622 760 1110 4000
mm W W % % mm2 % % % % % %
0 156.58 157 100.0 50.8 1.0 1.0 176400 5.6 13.0 19.6 18.2 27.5 16.0
Cell 1 Concentration Level 1882.951x, distance from lens 322.395mm, 0.9770f, nominal radius 5.461mm
1 0.225 9.58 10 6.1 24.4 67827.8 67827.8 0.16 7.4 5.2 0.0 0.0 23.7 63.6
2 0.450 8.28 18 11.4 38.2 19547.8 31620.0 0.48 8.8 6.3 0.0 0.1 38.3 46.5
3 0.675 7.04 25 15.9 64.7 9975.9 19596.9 0.80 10.7 8.1 0.0 0.7 66.1 14.4
4 0.900 6.54 31 20.1 64.5 6617.9 13918.4 1.11 12.1 10.3 0.0 1.4 65.6 10.5
5 1.125 6.00 37 23.9 59.1 4724.6 10608.4 1.43 13.9 14.5 0.0 2.3 59.3 10.0
6 1.350 6.51 44 28.1 57.0 4195.2 8649.1 1.75 12.9 20.2 0.0 5.5 53.2 8.2
7 1.575 9.03 53 33.8 52.3 4917.4 7659.0 2.07 6.6 34.4 6.2 10.8 34.8 7.3
8 1.800 10.85 64 40.8 53.3 5122.8 7064.6 2.39 1.7 24.9 15.4 18.2 30.3 9.5
9 2.025 9.71 74 47.0 53.4 4047.2 6431.3 2.70 1.8 21.1 16.3 24.0 26.6 10.1
10 2.250 8.87 82 52.6 53.0 3306.7 5837.7 3.02 1.9 18.9 17.1 34.0 17.3 10.8
11 2.475 8.24 91 57.9 52.9 2778.2 5306.7 3.34 1.9 16.6 17.6 36.5 16.2 11.2
12 2.700 7.69 98 62.8 52.7 2368.9 4837.4 3.66 1.9 14.8 18.7 36.2 16.8 11.6
13 2.925 7.19 106 67.4 52.5 2037.9 4423.3 3.98 2.0 13.0 20.5 35.3 17.2 12.1
14 3.150 6.73 112 71.7 52.2 1765.3 4057.2 4.29 2.0 11.4 22.4 34.2 17.5 12.5
15 3.375 6.32 119 75.7 51.8 1544.3 3733.3 4.61 2.0 10.1 24.4 32.9 17.7 13.0
16 3.600 5.90 124 79.5 51.5 1347.2 3444.4 4.93 2.1 8.4 26.7 31.2 18.1 13.5
17 3.825 5.56 130 83.0 51.1 1193.0 3187.3 5.25 2.1 7.1 29.1 29.6 18.2 14.0
18 4.050 5.23 135 86.4 51.0 1057.5 2957.2 5.57 2.1 5.6 31.7 27.5 18.7 14.4
19 4.275 4.92 140 89.5 51.1 941.3 2750.6 5.88 2.2 4.1 35.9 23.9 19.4 14.6
20 4.500 4.65 145 92.5 51.3 845.4 2564.8 6.20 2.2 2.8 43.6 17.0 20.1 14.4
Cell 2 Concentration Level 367.923x, distance from lens 347.204mm, 1.0521f, nominal radius 12.354mm
Last updated: 25 June 2010